Vapor generator



March 17, 1942. G. D. EB BETS 2,

VAPOR GENERATOR Filed Sept. 9, 1938 5 Sheets-Sheet l IN VENTOR.

GeorgeDEbbeis ATTORNEY.

March 17, 1942.

G. p. EBBETS VAPOR GENERATOR 3 Sheets-Sheet 2 Filed Sept. 9, 1938ATTORNEY.

Mach 17, 1942.

G. D. EBBETS VAPOR GENERATOR Filed Sept. 9, 1958.

3 Sheets-Sheet 3 QOOOOOOO Bai/er rufies OGOOGDOO Y fianamlzer 7216a;

INVENTOR.

- George D Ebbeis ATTORNEY.

Patented Mar. 17, 1942 VAPOR GENERATOR George D. Ebbets, Kenilworth, N.J., assignor to The Babcock & Wilcox Company, Newark, N. J a corporationof New Jersey Application September 9, 1938, Serial No. 229,074

Claims.

This invention relates to water tube steam boilers, and moreparticularly to bent tube boilers of the multiple drum type.

An object of the invention is to provide a bent tube boiler whichoperates at high efficiency.

More specifically, it is an object of the invention to provide a boilerwith an economizer which can be added to an installation withoutnecessitating any substantial change in the boiler setting or anyadditional economizer casing.

Other objects of the invention will appear as the accompanyingdescription proceeds.

The invention will be described with reference to the accompanyingdrawings in which preferred embodiments of the invention are shown.

In the drawings:

Fig. 1 is a vertical side section of the l-drum Stirling boiler;

Fig. 2 is a vertical section of the rear bank of a boiler, and showingthe relationship of the economizer to the boiler tubes;

Fig. 3 is a detail of a modified embodiment of the invention includingthe arrangement of the upper portion of the economizer with reference tothe rear drum;

Fig. 4 is a view similar to Fig. 3, but showing an additional embodimentof the invention;

Fig. 5 is a part of a horizontal section on the line 5-5 of Fig. 1;

Fig. 6 is a diagrammatic view in the nature of a transverse sectionthrough a rear bank of tubes arranged in accordance with the invention;

Fig. 7 is a view similar to Fig. 6 but showing a different arrangementof the economizer tubes in relation to the boiler tubes; and

Fig. 8 is a partial transverse section through a rear bank of tubes of amodification similar to that shown in Fig. 2, showing means forincreasing the heat transfer rates.

Referring to Fig. 1 of the drawings, the front upper drum I6 isconnected to the lower drum l2 by a bank of steam generating tubes l4which extend over the furnace chamber l6. These two drums are alsodirectly connected by tubes [8 which form a part of the middle bank oftubes I9.

Furnace gases passing from the furnace chamber I6 over the tubes I4 mustpass around the upper end of the bafile 20 which extends between the twofront rows of tubes I8, as shown in the drawings. Thence, the gases passdownwardly in a second gas pass between the bafiie 20 and a rearwardbafile 22 supported by some of the tubes 24 which directly connect thedrum l2 with the middle upper drum 26.

After passing from the second gas pass around the lower end of thebaflle 22, furnace gases pass through a third gas pass in which there isa rear bank of boiler tubes. This bank of tubes includes the tubes 28which directly connect the drums l2 and 26 and other tubes 30 whichdirectlyconnect the drum [2 with the rearmost upper drum, or the steamofftake drum 34. From the third gas pass the gases proceed upwardly pasta damper 36, to a flue.

A bafiie 2| extending from the setting wall I I2 across the tubes of therear bank causes the furnace gases to move across those tubes to thespace forwardly of that bank and then move again across the tubes asthey pass out of the boiler setting.

Excessive bypassing of the gases around the economizer (to be laterdescribed) in the rear bank is prevented by the baflle 23 which extendsfrom the economizer upwardly toward the baffie 25. The bafile 23,however, stops short of the bafiie 25 to provide a vent 21 for the gaspocket between the baflies 22 and 25.

The tubes 28 and 30 of the rear bank may be spaced as indicated in Fig.8 of the drawings, in which the rows of tubes A and B are more closelyspaced than the rows Band C. Similarly, the rows C and D are moreclosely spaced than D and E, etc. Between the more widely spaced rows B,C, D, and E, there are rows F and G of economizer tubes 40. These tubesare connected at their lower ends to the inlet header 42 which receivesfeed water from a suitable source. These tubes extend upwardly from theheader 42 with their main portions in parallelism with adjacent boilertubes of the rows A, B, C, and D, and at a position near the drum 34 theeconomizer tubes are bent rearwardly away from the rear bank of tubesfor connection to the upper economizer header 44. From that header, theheated feed water is discharged through the connections 46 into the drum34.

' When the boiler tubes of the rear bank, and the economizer tubes arearranged as indicated in Fig, 8 of the drawings, the spaces between someof the rows of boiler tubes, such as the rows A and B, on the one hand,and C and D, on the other hand, may be closed off by the heat resistantelements 50 at one or more positions. Such positions are indicated at52, 54, 56, and 58 in Fig. 2 of the drawings. These refractory elementsoperate to increase the velocity of the furnace gases in contact withparts of the economizer tubes and thereby increase the rates of heattransfer to the feed water in the economizer. Additional gas confiningbafiies 53 and 51 (Fig. 2) are used in conjunction with the baffleelements 50 in the Fig. 2 modification, and in the Fig. 1 modificationthe filter bafiles 55 (see also Fig, 7) are used above the cross bafli2|.

Fig. 6 of the drawings shows a modified arrangement of tubes for therear bank, the rows of the economizer tubes being indicated at -64,inclusive, while the rows of boiler tubes are indicated at -69,inclusive.

An arrangement of th tubes of the rear bank of the Fig. 1 modificationis indicated in Fig. 7 of the drawings, wherein the rows of economizertubes R, S, and T are arranged, respectively, between the rows A and-13, the rows C and D, and the rows E and L of the boiler tubes.

In the modification indicated in Fig. 3 of the drawings, the economizertubes 10 are connected to the economizer outlet header 12 which, inturn, is connected to the drum I4 by the tubes 16. The header I2 mayalso be vented to the steam space of the drum I4 by tubular connectionsI8 and 80 connected by the valve 82.

In the embodiment indicated in Fig. 4 of the drawings the economizertubes 84-89, inclusive, are directly connected to the drum 90 atpositions on opposit sides of the boiler tubes 92 of the rear bank.

Feed water, in passing upwardly from the economizer inlet header 42through the economizer tubes, is raised in temperature toward thesaturation temperature corresponding to the pressure under which theboiler is operating. In the boiler tubes adjacent the economizer tubesthe temperature of the water is always below the saturation temperaturebecause the water delivered by the economizer to the drum 34 is belowsaturation temperature. In this drum the incoming water from theeconomizer mixes with boiler water at saturation temperature, and theresulting mixture is therefore below the saturation temperature.

The illustrative boiler also includes the water circulators I00 directlyconnecting the drums I0 and 26, and the steam circulators I02 directlyconnecting the same drums. Steam is transmitted from the steam space ofthe drum 26 directly to the steam space of the drum 34 through the steamcirculators I04 and I06, and the steam passes from the drum 34 throughthe offtake connection I08 to a point of use.

The front and rear walls of the boiler setting indicated in Fig. 1 ofthe drawings are shown respectively at H0 and H2, the roof portions ofthe setting being defined and supported by the circulators I02 and I06.These roof portions are shown respectively at H4 and H6.

I claim:

1. In a water tube steam boiler, means forming a submerged waterchamber, upper drums, front and rear banks of tubes connecting the waterchamber to the upper drums, an economizer including upright tubes inrows positioned between the rows of boiler tubes of said rear bank oftubes and extending in parallelism therewith, said economizer tubeshaving their upper and outlet ends joined to a separate header or drumin communication with the rear upper drum, the lower ends of theeconomizer tubes being joined to a separate lower header or drum, andmeans for supplying feed water to the last mentioned separate header ordrum, there being normally no direct communication between. said Waterdrum and the lower ends of the economizer tubes.

2 In a water tube steam boiler, upper drums, means forming a submergedwater chamber, separated front and rear banks of boiler tubes directlyconnecting said water chamber with the upper drums, said tubes beingarranged in rows running transversely of the axes of said drums, aneconomizer including spaced tubes arranged in rows between some of therows of tubes in the rear bank, means for supplying feed water to thelower ends of the economizer tubes, means connecting the upper ends ofthe economizer tubes for discharge into the water space of the rearupper drum, and rows of refractory elements supported by the tubes ofthe rear bank and disposed between said tubes to increase the velocityof the furnace gases over the economizer tubes and consequently the rateof heat transfer from the furnace gases to the feed water in theeconomizer tubes, said refractory elements being arranged transverselyof gas flow and closing the spaces between boiler tubes of the rearbank.

*3. In a water tube steam boiler, upper and lower drums, two sets ofsubstantially parallel tubes arranged as a bank of tubes in a singlelongitudinal gas pass between the drums with the tubes of one setdirectly connecting the drums and providing a part of the boilercirculation circuit, separate upper and lower headers or drums for theremaining set of tubes, separated baflle members secured to some of thetubes and extending to adjacent tubes in said gas pass, said bafilemembers being disposed transversely of gas flow and arranged to closethe spaces between the boiler tubes, means for supplying feed water tothe lower header or drum for tubes of the second set, and meansconnecting the upper header or drum for the second set of tubes with theupper drum for the first set of tubes for the delivery of heated feedwater to the last mentioned drum.

4. In a water tube steam boiler, means forming a submerged waterchamber, upper drums, front and rear banks of tubes connecting the waterchamber to the upper drums, an economizer including rows of uprighttubes positioned between the rows of boiler tubes of said rear bank oftubes and extending in parallelism therewith, said economizer tubeshaving their outlet ends communicating with the rear drum, and separaterefractory elements between adjacent boiler tubes of the rear bank anddistributed across the gas flow to increase the velocity of the furnacegases over the economizer tubes, said refractory elements substantiallyclosing spaces between the boiler tubes of the rear bank.

5. In a water tube steam boiler, upper drums, means forming a submergedwater chamber, separated front and rear banks of boiler tubes directlyconnecting said water chamber with the upper drums, said tubes beingarranged in rows running transversely of the axes of said drums, aneconomizer including spaced tubes arranged in rows between some of therows of boiler tubes in the rear bank, a lower header to which theeconomizer tubes are connected, means for supplying feed water to theeconomizer tubes, an upper header to which the upper ends of theeconomizer tubes are connected, means connecting the upper header to thewater space of the rear upper drum, and rows of spaced refractoryelements supported by tubes of the rear bank and distributed across thegas flow to increase the velocity of the furnace gases over theeconomizer tubes and consequently the rate of heat transfer from thefurnace gases to the feed water in the economizer tubes, said refractoryelements closing spaces between adjacent boiler tubes of the rear bankand being arranged transversely of gas flow.

GEORGE D. EBBETS.

